Combustion spaces, such as, for example, a furnace, a hot-gas duct or a combustion chamber of a gas turbine, are known in which a hot medium is produced and/or directed. A thermally and/or thermomechanically highly loaded combustion space is provided with an appropriate lining in order to protect it from excessive thermal stressing. The lining of the combustion space is normally made of heat-resistant material and protects a wall of the combustion space from direct contact with the hot medium, for example a hot combustion gas, and from the associated high thermal loading. In addition, the combustion gases may have oxidative and/or corrosive constituents, which may have a lasting adverse effect on the combustion chamber wall if acted upon directly. There is therefore considerable interest in developing and improving the lining of a combustion space.
U.S. Pat. No. 4,840,131 discloses a fastening of ceramic lining elements to a wall of a furnace. In this case, a rail system which is fastened to the wall and has a plurality of ceramic rail elements is provided. The lining elements can be retained on the wall by the rail system. Further ceramic layers may be provided between a lining element and the wall of the furnace, inter alia a layer of loose, partly compressed ceramic fibers, this layer having at least the same thickness as the ceramic lining elements or a greater thickness. The lining elements in this case have a rectangular geometry with a planar surface. The lining elements are made of a heat-insulating refractory ceramic fiber material.
The application of a refractory lining to a wall of a furnace is likewise treated in U.S. Pat. No. 4,835,831. The refractory lining in this case is arranged in particular on a vertical wall. A layer consisting of glass fibers, ceramic fibers or mineral fibers is applied to the metallic wall of the furnace. This layer is fastened to the wall by metallic clamps or by adhesive. A wire mesh net having honeycomb meshes is applied to this layer. The mesh net likewise serves to protect the layer of ceramic fibers from falling down. By means of a suitable spraying process, a uniform closed surface of refractory material is applied to the layer fastened in this way. The method described largely avoids a situation in which refractory particles striking during the spraying are thrown back, as would be the case with direct spraying of the refractory particles onto the metallic wall.
Another type of lining of a thermally highly loaded combustion space is specified in EP 0 419 487 B1. The lining consists of thermal shielding elements which are mechanically retained on a metallic wall of the combustion space. The thermal shielding elements touch the metallic wall directly. In order to avoid excessive heating of the wall, e.g. as a result of direct heat transfer from the thermal shielding element or by ingress of hot medium into the gaps formed by the thermal shielding elements which adjoin one another, cooling air, the “sealing air”, is admitted to the space formed by the wall of the combustion space and the thermal shielding element. The sealing air prevents the penetration of hot medium up to the wall and at the same time cools the wall and the thermal shielding element.
EP 0 724 116 A2 discloses a ceramic lining for walls of thermally highly stressed combustion spaces, for example of gas-turbine combustion chambers. The lining consists of wall elements made of high-temperature-resistant structural ceramic, e.g. silicon carbide (SiC) or silicon nitride (Si3N4). The wall elements are elastically fastened to a metallic supporting structure (wall) of the combustion chamber in a mechanical manner by means of a central fastening bolt. A thick thermal insulating layer is provided between the wall element and the wall of the combustion space, so that the wall element is at an appropriate distance from the wall of the combustion chamber. The insulating layer, which in relation to the wall element is about three times as thick, is made of refractory ceramic material which is prefabricated in bricks. The dimensions and the external shape of the wall elements can be adapted to the geometry of the space to be lined.
A wall segment for a combustion space and a combustion space of a gas turbine are described in WO 99/47874. Specified in this case is a wall segment for a combustion space, to which a hot fluid can be admitted, having a metallic supporting structure and a thermal protection element fastened to the metallic supporting structure. Inserted between the metallic supporting structure and the thermal shielding element is a deformable separating layer, which is intended to absorb and compensate for possible relative movements of the thermal shielding element and the supporting structure. Such relative movements may be caused, for example, in the combustion chamber of a gas turbine, in particular an annular combustion chamber, by different thermal expansion behavior of the materials used or by pulsations in the combustion chamber, which may arise during irregular combustion for producing the hot working medium or due to resonance effects. At the same time, the separating layer causes the relatively inelastic thermal protection element to rest in a more planar manner overall on the separating layer and the metallic supporting structure, since the thermal protection element penetrates at least partly into the separating elements. The separating layer is thus also able to compensate for production-related unevenness on the supporting structure and/or the thermal protection element, which unevenness may lead locally to an unfavorable concentrated introduction of force.